Two former Parramatta Eels players are accused of harbouring semi-automatic weapons and possessing more than half-a-million dollars in cash after dramatic arrests in Sydney's Centennial Park yesterday.

Real estate agent and father of three older children Rob McIntosh, 52, of North Pole, Alaska, was near the front of the stage with friends when the shooting began, according to friend and real estate broker Mike Vansickle.

He was hit repeatedly but survived, Mr Vansickle said.

"From just getting off the phone with the family he took three bullets to his body," Mr Vansickle said.

"He just came out of surgery, and he's going to make it."

Mr Vansickle described his friend as strong.

"He's been though lots of adversity," he said.

"He'll get through all this and come out with some stories to tell."

Among the injured were two off-duty personnel from the Los Angeles Sheriff's Department, the agency confirmed. Both were transported to a local hospital after being hit by gunfire.

One remains in critical condition and the other is in stable condition, the department said in a statement. No names or details on their positions at the department were being released at this time.

Police crouch behind a patrol car with their weapons trained on the casino. (Getty Images)A body, which has been pixelated, lies on the ground amid rubbish at the concert. (Getty Images)

Authorities in Las Vegas have warned that identifying bodies from the shooting would be a "long, laborious process".

Clark County Sheriff Joseph Lombardo also said Monday local time that investigators were continuing their collection of evidence and working to reunite people with relatives who were at the shooting site.

Police said Paddock was on the 32nd floor of the Mandalay Bay casino-hotel tower Sunday night when he opened fire at concertgoers at the Route 91 Harvest festival.

Festivalgoers are seen running from the event at the Mandalay Bay Resort and Casino. (Getty Images)People are shown running from the concert. (Getty Images)Festivalgoers are seen running from the event at the Mandalay Bay Resort and Casino. (Getty Images)

Authorities have set up hotlines and centers to help people track down relatives.

Mr Lombardo said he expected a convention center to be used for that because authorities needed a large space.